NEW YORK (CBSNewYork) — Home improvement giant Home Depot on Tuesday was investigating a potential credit card breach that some cyber security experts said could be massive.

As CBS 2’s Matt Kozar reported, Home Depot has confirmed that it is working with investigators after reports that stolen debit and credit card information from its customers was being sold on the black market.

How many stores and customers were affected remained unknown Tuesday.

“It’s definitely a problem, and it’s a concern for me,” said Home Depot shopper Judy Anderson. “You know, it just makes you think twice before using a credit card.”

Home Depot shoppers in Jersey City were unnerved by the potential data theft.

“For everyday needs, we come to these stores, and we use credit cards, so if hackers get in their databases, obviously that concerns,” said Home Depot shopper Avnish Choudhury.

In a statement, Home Depot senior manager for corporate communications Paula Drake said, “Protecting our customers’ information is something we take extremely seriously, and we are aggressively gathering facts at this point while working to protect customers.”

Reportedly, the hackers responsible for the apparent breach were European — possibly Russian. Russian hackers have been targeting American business in retaliation for U.S. sanctions.

“Hackers come from many different countries, and many different motives,” said fraud expert Mary Ann Miller.

Miller is a senior director at NICE Actimize, a financial crime software company. She recommended that new chip credit cards, which have a microchip embedded in the plastic, are safer to use than traditional credit cards with a black strip.

Miller said American companies will begin rolling out the new cards in a few weeks.

“If a data breach happens again, that data will be much less valuable to the fraudsters and hackers,” she said.

It was not clear Tuesday afternoon how many stores may have been impacted, but preliminary analysis indicated that the breach may extend across all 2,200 Home Depot stores in the United States.